Following my recent post on butter vs margarine, I realise one alternative people tend to reach for is soya butter, therefore I feel it's appropriate to raise a discussion about the great soy debate!
Soy (made from the soybean) is a complete protein, which means it provides all the essential amino acids needed by the body, and this makes it a sensible food choice for vegetarians and vegans who don't have animal protein in their diet. Soy beans are a good source of protein, are low on the Glycaemic Index so help to balance blood sugar levels, can help to lower cholesterol and are a good source of iron. Soy butter and milk may be a good dairy alternative not only because they are suitable for vegetarians and vegans but also because many people have trouble with digesting cow's milk. Furthermore, soy products contain less fat and fewer calories than the dairy alternatives, so may be popular with people for this reason.
So why the debate?
There is a difference between unfermented soy (such as soy milk and meat alternatives such as sausages) and fermented soy such as tempeh and miso.
Unfermented soy contains 'anti-nutrients' which are phytates, enzyme inhibitors and goitrogens. Phytates can stop the absorption of nutrients in the intestines, such as calcium, iron and zinc. This can be a problem for anyone but particularly people who limit certain foods from their diets as they may have low levels of some nutrients anyway. Enzyme inhibitors interfere with the process of digestive enzymes breaking down food to be assimilated in to the body. This means food may not be completely digested and this can cause problems with bacteria. Goitrogens are substances which affect thyroid function by interfering with the absorption of iodine, so could have a negative effect on people who suffer from hypothyroidism. Furthermore, it may interfere with the absorption of the medication given in these cases. Due to these factors unfermented soy may be linked to a number of health issues such as digestive and immune disorders, allergies, malnutrition and a higher risk of heart disease.
Fermented soy has lower levels of these anti-nutrients and is easier to digest then unfermented, and therefore may be more highly recommended.
Soy contains isoflavones, which are phytoestrogens which help to balance oestrogen in the body and have been studied for their prevention of hormone-related cancers, as well as for their role in the management of menopause and potential lowering effect on cholesterol levels. Only fermented soy contains isoflavones in the correct form to be used in the body.
However, these isoflavones may affect thyroid health and the action of hormones so still fermented soy should be eaten in caution in some cases.
Did you know that other foods also contain anti-nutrients? Vegetables such as broccoli, cabbage, bok choi and even fruits such as strawberries contain some substances that may be harmful in large quantities, but usually soaking or the action of cooking them would remove these substances.
On the whole I believe in 'everything in moderation', though I also believe we are all different and what works for one person may not work for another. We can't always be afraid of eating foods because of what we read about them otherwise we will eventually be eating very little!
In the case of soy I would always assess based on the individual, rather than giving a blanket yes or no regardless of a person's health status (though I know some people who do give a definitive yes or no, and I respect other people's opinions). In general we all know that processed foods are less nutritious than their fresh alternatives, and this includes soy so I would generally advise limiting it for this reason. Furthermore, soy products are often genetically modified so I would always recommend looking for non-GM products.
Alternatives to dairy and soy milk include goat's, rice, coconut, almond and even the brand Lactofree if it's just lactose someone is trying to avoid. Personally I can't taste the difference between regular and rice milk, but I am not a milk drinker as such so this makes it easier. There are many non-dairy sources of calcium so don't feel that you need to drink milk to get an adequate calcium intake.
I am interested to hear your thoughts!
